Influence of Pollution Degree on Impact Flashover Characteristics of Insulator

The flashover characteristics of polluted insulators under lightning impulse and switching impulse are simulated in laboratory. It is found that when the gray density value is fixed, the flashover voltage begins to saturate under the shielding failure voltage while the salt density value reaches 0.1∼0.15mg/cm² And the salt density saturation point under the counterattack voltage waveform is earlier than that under the counterattack voltage waveform, around 0.02mg/cm². When the gray density value is fixed, under the counterattack voltage waveform, the flashover voltage decreases slightly in the gray density of 0.05mg/cm² to 0.10 mg/cm² range, and the flashover voltage begins to rise with the increase of gray density. Under the shielding failure waveform, the flashover voltage always decreases in the gray density of 0.05mg/cm² to 0.20mg/cm²range, and begins to rise gradually after the gray density exceeds 0.20mg/cm². (paper)